In marine vessels it is known that various systems such as air conditioning, bilge pumps, and water drains, discharge water overboard directly into the body of water in which the vessel is present in.
This discharge of water makes an audible sound when the discharge water contacts the main body of water in which the vessel is present in. This discharge water is typically introduced to the primary body of water in a free stream form, exiting the side or hull of the vessel falling to the surface of the surrounding water. In these cases it is desirable to reintroduce the discharge water at a controlled rate at or below the surface of the surrounding water, allowing the discharge noise to be substantially reduced.